Prince Sergei Nikolaevich Trubetskoy was a Russian religious philosopher. He was the son of Prince Nikolai Petrovitch Trubetskoy, co-founder of the Moscow Conservatory, and Sophia Alekseievna Lopouchina, who was a big influence on his religious thought. Trubetskoy and his brother, Evgenii Nikolaevitch Troubetzkoy (1863–1920), continued Vladimir Solovyov's work on developing a modern Christian philosophy of the world. He was also a professor of philosophy at Moscow University and a founding member of the underground discussion circle Beseda.
